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INFO: rcu detected stall in __unwind_start (2)

Status: auto-obsoleted due to no activity on 2025/11/08 01:37
Subsystems: kernel
[Documentation on labels]
First crash: 142d, last: 121d
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: rcu detected stall in __unwind_start net virt 1 2 504d 535d 0/29 auto-obsoleted due to no activity on 2024/10/21 04:09

Sample crash report:
bridge0: received packet on veth0_to_bridge with own address as source address (addr:46:21:d1:00:28:23, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:46:21:d1:00:28:23, vlan:0)
rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5844/1:b..l P2/1:b..l P17875/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=161089, q=621 ncpus=1)
task:kworker/u11:1   state:R  running task     stack:21816 pid:17875 tgid:17875 ppid:2      task_flags:0x4208160 flags:0x00004000
Workqueue: kvfree_rcu_reclaim kfree_rcu_monitor
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5397 [inline]
 __schedule+0x116a/0x5de0 kernel/sched/core.c:6786
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7109
 irqentry_exit+0x36/0x90 kernel/entry/common.c:307
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_release+0x183/0x2f0 kernel/locking/lockdep.c:5896
Code: 0f c1 05 c8 53 37 12 83 f8 01 0f 85 1d 01 00 00 9c 58 f6 c4 02 0f 85 08 01 00 00 41 f7 c5 00 02 00 00 74 01 fb 48 8b 44 24 10 <65> 48 2b 05 dd 11 37 12 0f 85 58 01 00 00 48 83 c4 18 5b 41 5c 41
RSP: 0018:ffffc9000214f620 EFLAGS: 00000206
RAX: 323f9fc74cd63b00 RBX: ffffffff8e5c4c80 RCX: ffffc9000214f62c
RDX: 0000000000000003 RSI: ffffffff8de0448a RDI: ffffffff8c155ce0
RBP: 0000000000000001 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000006abc R12: ffffffff816a9ac4
R13: 0000000000000206 R14: ffff88805b640000 R15: 0000000000000004
 rcu_lock_release include/linux/rcupdate.h:341 [inline]
 rcu_read_unlock include/linux/rcupdate.h:871 [inline]
 class_rcu_destructor include/linux/rcupdate.h:1155 [inline]
 unwind_next_frame+0x3f9/0x20a0 arch/x86/kernel/unwind_orc.c:479
 __unwind_start+0x45f/0x7f0 arch/x86/kernel/unwind_orc.c:758
 unwind_start arch/x86/include/asm/unwind.h:64 [inline]
 arch_stack_walk+0x73/0x100 arch/x86/kernel/stacktrace.c:24
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
 kasan_save_track+0x14/0x30 mm/kasan/common.c:68
 kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x51/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2381 [inline]
 slab_free_freelist_hook mm/slub.c:2410 [inline]
 slab_free_bulk mm/slub.c:4667 [inline]
 kmem_cache_free_bulk.part.0+0x383/0x7f0 mm/slub.c:5246
 kfree_bulk include/linux/slab.h:794 [inline]
 kvfree_rcu_bulk+0x1b7/0x1e0 mm/slab_common.c:1516
 kvfree_rcu_drain_ready mm/slab_common.c:1699 [inline]
 kfree_rcu_monitor+0x1d0/0x2f0 mm/slab_common.c:1772
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3321 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
task:kthreadd        state:R  running task     stack:26968 pid:2     tgid:2     ppid:0      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5397 [inline]
 __schedule+0x116a/0x5de0 kernel/sched/core.c:6786
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7109
 irqentry_exit+0x36/0x90 kernel/entry/common.c:307
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__page_table_check_zero+0x193/0x5d0 mm/page_table_check.c:139
Code: fc ff df 48 c1 e8 03 80 3c 10 00 0f 85 20 04 00 00 48 2b 1d cf 50 c7 0b 41 bd 01 00 00 00 31 ed 49 bf 00 00 00 00 00 fc ff df <48> c1 fb 06 48 89 df 48 89 5c 24 10 e8 6c d8 ff ff 44 89 f1 41 d3
RSP: 0018:ffffc90000077808 EFLAGS: 00000246
RAX: 1ffffffff1be5888 RBX: 0000000001f41800 RCX: ffffffff822b7660
RDX: dffffc0000000000 RSI: ffffffff822b734b RDI: 0000000000000001
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000
R13: 0000000000000001 R14: 0000000000000003 R15: dffffc0000000000
 page_table_check_free include/linux/page_table_check.h:43 [inline]
 free_pages_prepare mm/page_alloc.c:1249 [inline]
 __free_frozen_pages+0x7df/0x1180 mm/page_alloc.c:2706
 discard_slab mm/slub.c:2717 [inline]
 __put_partials+0x16d/0x1c0 mm/slub.c:3186
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4d/0x120 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:329
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4148 [inline]
 slab_alloc_node mm/slub.c:4197 [inline]
 __do_kmalloc_node mm/slub.c:4327 [inline]
 __kmalloc_noprof+0x1d4/0x510 mm/slub.c:4340
 kmalloc_noprof include/linux/slab.h:909 [inline]
 kzalloc_noprof include/linux/slab.h:1039 [inline]
 lsm_blob_alloc+0x68/0x90 security/security.c:684
 lsm_task_alloc security/security.c:771 [inline]
 security_task_alloc+0x2d/0x260 security/security.c:3160
 copy_process+0x2205/0x7650 kernel/fork.c:2151
 kernel_clone+0xfc/0x960 kernel/fork.c:2599
 kernel_thread+0xd4/0x120 kernel/fork.c:2661
 create_kthread kernel/kthread.c:487 [inline]
 kthreadd+0x503/0x800 kernel/kthread.c:847
 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
task:syz-executor    state:R  running task     stack:22040 pid:5844  tgid:5844  ppid:1      task_flags:0x400140 flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5397 [inline]
 __schedule+0x116a/0x5de0 kernel/sched/core.c:6786
 preempt_schedule_irq+0x51/0x90 kernel/sched/core.c:7109
 irqentry_exit+0x36/0x90 kernel/entry/common.c:307
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:unwind_next_frame+0x50c/0x20a0 arch/x86/kernel/unwind_orc.c:505
Code: e8 19 f1 ff ff 48 89 c1 48 85 c0 0f 84 05 fe ff ff 48 b8 00 00 00 00 00 fc ff df 4c 8d 79 05 4c 89 fa 48 c1 ea 03 0f b6 04 02 <4c> 89 fa 83 e2 07 38 d0 7f 08 84 c0 0f 85 32 14 00 00 0f b6 41 05
RSP: 0018:ffffc90003f7f630 EFLAGS: 00000a06
RAX: 0000000000000000 RBX: 0000000000000001 RCX: ffffffff91f2f35e
RDX: 1ffffffff23e5e6c RSI: 0000000000000000 RDI: ffffffff9132ed74
RBP: ffffc90003f7f6e8 R08: ffffffff91f2f364 R09: 0000000000000000
R10: 0000000000000000 R11: 00000000000a8221 R12: ffffc90003f7f6f0
R13: ffffc90003f7f6a0 R14: ffffc90003f7f6d5 R15: ffffffff91f2f363
 arch_stack_walk+0x94/0x100 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122
 save_stack+0x160/0x1f0 mm/page_owner.c:156
 __reset_page_owner+0x84/0x1a0 mm/page_owner.c:308
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1248 [inline]
 __free_frozen_pages+0x7fe/0x1180 mm/page_alloc.c:2706
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x4d/0x120 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x195/0x1e0 mm/kasan/quarantine.c:286
 __kasan_kmalloc+0x8a/0xb0 mm/kasan/common.c:385
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __do_kmalloc_node mm/slub.c:4328 [inline]
 __kmalloc_noprof+0x223/0x510 mm/slub.c:4340
 kmalloc_noprof include/linux/slab.h:909 [inline]
 tomoyo_realpath_from_path+0xc2/0x6e0 security/tomoyo/realpath.c:251
 tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
 tomoyo_path_perm+0x274/0x460 security/tomoyo/file.c:822
 security_inode_getattr+0x116/0x290 security/security.c:2377
 vfs_getattr fs/stat.c:259 [inline]
 vfs_fstat+0x4b/0xe0 fs/stat.c:281
 vfs_fstatat+0xbc/0xf0 fs/stat.c:373
 __do_sys_newfstatat+0x97/0x120 fs/stat.c:542
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc5a698d1ba
RSP: 002b:00007fff7b974f08 EFLAGS: 00000206 ORIG_RAX: 0000000000000106
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007fc5a698d1ba
RDX: 00007fff7b974f10 RSI: 00007fc5a6a4db62 RDI: 0000000000000003
RBP: 00007fff7b974f10 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000001000 R11: 0000000000000206 R12: 00007fff7b976110
R13: 00007fc5a6a10b55 R14: 00000000000fd91c R15: 00007fff7b976150
 </TASK>
rcu: rcu_preempt kthread starved for 383 jiffies! g161089 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: 	Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt     state:R  running task     stack:28664 pid:16    tgid:16    ppid:2      task_flags:0x208040 flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5397 [inline]
 __schedule+0x116a/0x5de0 kernel/sched/core.c:6786
 __schedule_loop kernel/sched/core.c:6864 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:6879
 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99
 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2054
 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2256
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 3412 Comm: kworker/R-bat_e Tainted: G     U              6.16.0-rc6-syzkaller-00253-g4871b7cb27f4 #0 PREEMPT(full) 
Tainted: [U]=USER
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: bat_events batadv_dat_purge
RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x8/0x70 kernel/kcov.c:216
Code: e9 fd 55 59 00 be 03 00 00 00 5b e9 62 fe 1b 03 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 34 24 <65> 48 8b 15 a8 ca 13 12 65 8b 05 b9 ca 13 12 a9 00 01 ff 00 74 1d
RSP: 0018:ffffc900000069e0 EFLAGS: 00000202
RAX: 0000000000000000 RBX: ffff88805dd88000 RCX: ffffffff8a318ec8
RDX: ffff888032033c00 RSI: ffffffff8a318da9 RDI: 0000000000000005
RBP: dffffc0000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000001
R13: ffffc90000006cf0 R14: 0000000000000000 R15: ffff88805dd834c8
FS:  0000000000000000(0000) GS:ffff88812472e000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2ed3c00218 CR3: 000000000e382000 CR4: 00000000003526f0
Call Trace:
 <IRQ>
 __find_rr_leaf+0x259/0xe00 net/ipv6/route.c:833
 find_rr_leaf net/ipv6/route.c:890 [inline]
 rt6_select net/ipv6/route.c:934 [inline]
 fib6_table_lookup+0x57c/0xa30 net/ipv6/route.c:2232
 ip6_pol_route+0x1cc/0x1230 net/ipv6/route.c:2268
 pol_lookup_func include/net/ip6_fib.h:617 [inline]
 fib6_rule_lookup+0x536/0x720 net/ipv6/fib6_rules.c:120
 ip6_route_input_lookup net/ipv6/route.c:2337 [inline]
 ip6_route_input+0x662/0xc00 net/ipv6/route.c:2640
 ip6_rcv_finish_core.constprop.0+0x1a0/0x5d0 net/ipv6/ip6_input.c:66
 ip6_rcv_finish+0x130/0x5b0 net/ipv6/ip6_input.c:77
 ip_sabotage_in+0x21e/0x290 net/bridge/br_netfilter_hooks.c:993
 nf_hook_entry_hookfn include/linux/netfilter.h:157 [inline]
 nf_hook_slow+0xbe/0x200 net/netfilter/core.c:623
 nf_hook.constprop.0+0x422/0x750 include/linux/netfilter.h:272
 NF_HOOK include/linux/netfilter.h:315 [inline]
 ipv6_rcv+0xa4/0x680 net/ipv6/ip6_input.c:309
 __netif_receive_skb_one_core+0x12d/0x1e0 net/core/dev.c:5977
 __netif_receive_skb+0x1d/0x160 net/core/dev.c:6090
 netif_receive_skb_internal net/core/dev.c:6176 [inline]
 netif_receive_skb+0x137/0x7b0 net/core/dev.c:6235
 NF_HOOK include/linux/netfilter.h:317 [inline]
 NF_HOOK include/linux/netfilter.h:311 [inline]
 br_pass_frame_up+0x346/0x490 net/bridge/br_input.c:70
 br_handle_frame_finish+0xf5a/0x1ca0 net/bridge/br_input.c:227
 br_nf_hook_thresh+0x307/0x410 net/bridge/br_netfilter_hooks.c:1170
 br_nf_pre_routing_finish_ipv6+0x76a/0xfb0 net/bridge/br_netfilter_ipv6.c:154
 NF_HOOK include/linux/netfilter.h:317 [inline]
 br_nf_pre_routing_ipv6+0x3cd/0x8c0 net/bridge/br_netfilter_ipv6.c:184
 br_nf_pre_routing+0x860/0x15b0 net/bridge/br_netfilter_hooks.c:508
 nf_hook_entry_hookfn include/linux/netfilter.h:157 [inline]
 nf_hook_bridge_pre net/bridge/br_input.c:283 [inline]
 br_handle_frame+0xad5/0x14b0 net/bridge/br_input.c:434
 __netif_receive_skb_core.constprop.0+0xa23/0x4a00 net/core/dev.c:5863
 __netif_receive_skb_one_core+0xb0/0x1e0 net/core/dev.c:5975
 __netif_receive_skb+0x1d/0x160 net/core/dev.c:6090
 process_backlog+0x442/0x15e0 net/core/dev.c:6442
 __napi_poll.constprop.0+0xba/0x550 net/core/dev.c:7414
 napi_poll net/core/dev.c:7478 [inline]
 net_rx_action+0xa9f/0xfe0 net/core/dev.c:7605
 handle_softirqs+0x219/0x8e0 kernel/softirq.c:579
 do_softirq kernel/softirq.c:480 [inline]
 do_softirq+0xb2/0xf0 kernel/softirq.c:467
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0x100/0x120 kernel/softirq.c:407
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 __batadv_dat_purge.part.0+0x279/0x3a0 net/batman-adv/distributed-arp-table.c:185
 __batadv_dat_purge net/batman-adv/distributed-arp-table.c:166 [inline]
 batadv_dat_purge+0x4b/0xa0 net/batman-adv/distributed-arp-table.c:204
 process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3321 [inline]
 rescuer_thread+0x620/0xea0 kernel/workqueue.c:3498
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
net_ratelimit: 2134 callbacks suppressed
bridge0: received packet on veth0_to_bridge with own address as source address (addr:46:21:d1:00:28:23, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:46:21:d1:00:28:23, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:46:21:d1:00:28:23, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:46:21:d1:00:28:23, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:46:21:d1:00:28:23, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:46:21:d1:00:28:23, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:46:21:d1:00:28:23, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:46:21:d1:00:28:23, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:46:21:d1:00:28:23, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:46:21:d1:00:28:23, vlan:0)
net_ratelimit: 3535 callbacks suppressed
bridge0: received packet on veth0_to_bridge with own address as source address (addr:46:21:d1:00:28:23, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:46:21:d1:00:28:23, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:46:21:d1:00:28:23, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:46:21:d1:00:28:23, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:46:21:d1:00:28:23, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:46:21:d1:00:28:23, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:46:21:d1:00:28:23, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:46:21:d1:00:28:23, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:46:21:d1:00:28:23, vlan:0)
bridge0: received packet on veth0_to_bridge with own address as source address (addr:46:21:d1:00:28:23, vlan:0)

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/19 13:05 upstream 4871b7cb27f4 7117feec .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto INFO: rcu detected stall in __unwind_start
2025/08/10 01:33 net 33caa208dba6 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce INFO: rcu detected stall in __unwind_start
* Struck through repros no longer work on HEAD.